Pulse- or frame-based communication using active stylus

ABSTRACT

In one embodiment, a method includes receiving sensor data from one or more sensors in or on a stylus, the stylus including one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for wirelessly transmitting signals to a device through a touch sensor of the device. The method includes generating a carrier signal and modulating the carrier signal to communicate the sensor data and wirelessly transmitting from the stylus to the device the carrier signal as modulated through the touch sensor of the device.

RELATED APPLICATIONS

This application is a continuation, under 35 U.S.C. 120, of U.S. patentapplication Ser. No. 13/363,043, filed 31 Jan. 2012, which claims thebenefit, under 35 U.S.C. §119(e), of U.S. Provisional Patent ApplicationNo. 61/553,114, filed 28 Oct. 2011.

TECHNICAL FIELD

This disclosure generally relates to touch sensors.

BACKGROUND

A touch sensor may detect the presence and location of a touch or theproximity of an object (such as a user's finger or a stylus) within atouch-sensitive area of the touch sensor overlaid on a display screen,for example. In a touch-sensitive-display application, the touch sensormay enable a user to interact directly with what is displayed on thescreen, rather than indirectly with a mouse or touch pad. A touch sensormay be attached to or provided as part of a desktop computer, laptopcomputer, tablet computer, personal digital assistant (PDA), smartphone,satellite navigation device, portable media player, portable gameconsole, kiosk computer, point-of-sale device, or other suitable device.A control panel on a household or other appliance may include a touchsensor.

There are a number of different types of touch sensors, such as, forexample, resistive touch screens, surface acoustic wave touch screens,and capacitive touch screens. Herein, reference to a touch sensor mayencompass a touch screen, and vice versa, where appropriate. When anobject touches or comes within proximity of the surface of thecapacitive touch screen, a change in capacitance may occur within thetouch screen at the location of the touch or proximity. A touch-sensorcontroller may process the change in capacitance to determine itsposition on the touch screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example touch sensor with an example touch-sensorcontroller.

FIG. 2 illustrates an example active stylus exterior.

FIG. 3 illustrates an example active stylus interior.

FIG. 4 illustrates an example active stylus with touch sensor device.

FIG. 5 illustrates an example touch-sensitive area of a touch sensordevice.

FIG. 6 illustrates an example method for communication from an activestylus to a touch sensor device.

FIG. 7A illustrates an example method for communicating modulated databetween an active stylus and a device.

FIG. 7B illustrates an example method for communicating modulated databetween an active stylus and a device.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 illustrates an example touch sensor 10 with an exampletouch-sensor controller 12. Touch sensor 10 and touch-sensor controller12 may detect the presence and location of a touch or the proximity ofan object within a touch-sensitive area of touch sensor 10. Herein,reference to a touch sensor may encompass both the touch sensor and itstouch-sensor controller, where appropriate. Similarly, reference to atouch-sensor controller may encompass both the touch-sensor controllerand its touch sensor, where appropriate. Touch sensor 10 may include oneor more touch-sensitive areas, where appropriate. Touch sensor 10 mayinclude an array of drive and sense electrodes (or an array ofelectrodes of a single type) disposed on one or more substrates, whichmay be made of a dielectric material. Herein, reference to a touchsensor may encompass both the electrodes of the touch sensor and thesubstrate(s) that they are disposed on, where appropriate.Alternatively, where appropriate, reference to a touch sensor mayencompass the electrodes of the touch sensor, but not the substrate(s)that they are disposed on.

An electrode (whether a ground electrode, guard electrode, driveelectrode, or sense electrode) may be an area of conductive materialforming a shape, such as for example a disc, square, rectangle, thinline, other suitable shape, or suitable combination of these. One ormore cuts in one or more layers of conductive material may (at least inpart) create the shape of an electrode, and the area of the shape may(at least in part) be bounded by those cuts. In particular embodiments,the conductive material of an electrode may occupy approximately 100% ofthe area of its shape. As an example and not by way of limitation, anelectrode may be made of indium tin oxide (ITO) and the ITO of theelectrode may occupy approximately 100% of the area of its shape(sometimes referred to as a 100% fill), where appropriate. In particularembodiments, the conductive material of an electrode may occupysubstantially less than 100% of the area of its shape. As an example andnot by way of limitation, an electrode may be made of fine lines ofmetal or other conductive material (FLM), such as for example copper,silver, or a copper- or silver-based material, and the fine lines ofconductive material may occupy approximately 5% of the area of its shapein a hatched, mesh, or other suitable pattern. Herein, reference to FLMencompasses such material, where appropriate. Although this disclosuredescribes or illustrates particular electrodes made of particularconductive material forming particular shapes with particular fillpercentages having particular patterns, this disclosure contemplates anysuitable electrodes made of any suitable conductive material forming anysuitable shapes with any suitable fill percentages having any suitablepatterns.

Where appropriate, the shapes of the electrodes (or other elements) of atouch sensor may constitute in whole or in part one or moremacro-features of the touch sensor. One or more characteristics of theimplementation of those shapes (such as, for example, the conductivematerials, fills, or patterns within the shapes) may constitute in wholeor in part one or more micro-features of the touch sensor. One or moremacro-features of a touch sensor may determine one or morecharacteristics of its functionality, and one or more micro-features ofthe touch sensor may determine one or more optical features of the touchsensor, such as transmittance, refraction, or reflection.

A mechanical stack may contain the substrate (or multiple substrates)and the conductive material forming the drive or sense electrodes oftouch sensor 10. As an example and not by way of limitation, themechanical stack may include a first layer of optically clear adhesive(OCA) beneath a cover panel. The cover panel may be clear and made of aresilient material suitable for repeated touching, such as for exampleglass, polycarbonate, or poly(methyl methacrylate) (PMMA). Thisdisclosure contemplates any suitable cover panel made of any suitablematerial. The first layer of OCA may be disposed between the cover paneland the substrate with the conductive material forming the drive orsense electrodes. The mechanical stack may also include a second layerof OCA and a dielectric layer (which may be made of PET or anothersuitable material, similar to the substrate with the conductive materialforming the drive or sense electrodes). As an alternative, whereappropriate, a thin coating of a dielectric material may be appliedinstead of the second layer of OCA and the dielectric layer. The secondlayer of OCA may be disposed between the substrate with the conductivematerial making up the drive or sense electrodes and the dielectriclayer, and the dielectric layer may be disposed between the second layerof OCA and an air gap to a display of a device including touch sensor 10and touch-sensor controller 12. As an example only and not by way oflimitation, the cover panel may have a thickness of approximately 1 mm;the first layer of OCA may have a thickness of approximately 0.05 mm;the substrate with the conductive material forming the drive or senseelectrodes may have a thickness of approximately 0.05 mm; the secondlayer of OCA may have a thickness of approximately 0.05 mm; and thedielectric layer may have a thickness of approximately 0.05 mm. Althoughthis disclosure describes a particular mechanical stack with aparticular number of particular layers made of particular materials andhaving particular thicknesses, this disclosure contemplates any suitablemechanical stack with any suitable number of any suitable layers made ofany suitable materials and having any suitable thicknesses. As anexample and not by way of limitation, in particular embodiments, a layerof adhesive or dielectric may replace the dielectric layer, second layerof OCA, and air gap described above, with there being no air gap to thedisplay.

One or more portions of the substrate of touch sensor 10 may be made ofpolyethylene terephthalate (PET) or another suitable material. Thisdisclosure contemplates any suitable substrate with any suitableportions made of any suitable material. In particular embodiments, thedrive or sense electrodes in touch sensor 10 may be made of ITO in wholeor in part. In particular embodiments, the drive or sense electrodes intouch sensor 10 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, one or moreportions of the conductive material may be copper or copper-based andhave a thickness of approximately 5 μm or less and a width ofapproximately 10 μm or less. As another example, one or more portions ofthe conductive material may be silver or silver-based and similarly havea thickness of approximately 5 μm or less and a width of approximately10 μm or less. This disclosure contemplates any suitable electrodes madeof any suitable material.

Touch sensor 10 may implement a capacitive form of touch sensing. In amutual-capacitance implementation, touch sensor 10 may include an arrayof drive and sense electrodes forming an array of capacitive nodes. Adrive electrode and a sense electrode may form a capacitive node. Thedrive and sense electrodes forming the capacitive node may come neareach other, but not make electrical contact with each other. Instead,the drive and sense electrodes may be capacitively coupled to each otheracross a space between them. A pulsed or alternating voltage applied tothe drive electrode (by touch-sensor controller 12) may induce a chargeon the sense electrode, and the amount of charge induced may besusceptible to external influence (such as a touch or the proximity ofan object). When an object touches or comes within proximity of thecapacitive node, a change in capacitance may occur at the capacitivenode and touch-sensor controller 12 may measure the change incapacitance. By measuring changes in capacitance throughout the array,touch-sensor controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10.

In a self-capacitance implementation, touch sensor 10 may include anarray of electrodes of a single type that may each form a capacitivenode. When an object touches or comes within proximity of the capacitivenode, a change in self-capacitance may occur at the capacitive node andcontroller 12 may measure the change in capacitance, for example, as achange in the amount of charge needed to raise the voltage at thecapacitive node by a pre-determined amount. As with a mutual-capacitanceimplementation, by measuring changes in capacitance throughout thearray, controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10. Thisdisclosure contemplates any suitable form of capacitive touch sensing,where appropriate.

In particular embodiments, one or more drive electrodes may togetherform a drive line running horizontally or vertically or in any suitableorientation. Similarly, one or more sense electrodes may together form asense line running horizontally or vertically or in any suitableorientation. In particular embodiments, drive lines may runsubstantially perpendicular to sense lines. Herein, reference to a driveline may encompass one or more drive electrodes making up the driveline, and vice versa, where appropriate. Similarly, reference to a senseline may encompass one or more sense electrodes making up the senseline, and vice versa, where appropriate.

Touch sensor 10 may have drive and sense electrodes disposed in apattern on one side of a single substrate. In such a configuration, apair of drive and sense electrodes capacitively coupled to each otheracross a space between them may form a capacitive node. For aself-capacitance implementation, electrodes of only a single type may bedisposed in a pattern on a single substrate. In addition or as analternative to having drive and sense electrodes disposed in a patternon one side of a single substrate, touch sensor 10 may have driveelectrodes disposed in a pattern on one side of a substrate and senseelectrodes disposed in a pattern on another side of the substrate.Moreover, touch sensor 10 may have drive electrodes disposed in apattern on one side of one substrate and sense electrodes disposed in apattern on one side of another substrate. In such configurations, anintersection of a drive electrode and a sense electrode may form acapacitive node. Such an intersection may be a location where the driveelectrode and the sense electrode “cross” or come nearest each other intheir respective planes. The drive and sense electrodes do not makeelectrical contact with each other—instead they are capacitively coupledto each other across a dielectric at the intersection. Although thisdisclosure describes particular configurations of particular electrodesforming particular nodes, this disclosure contemplates any suitableconfiguration of any suitable electrodes forming any suitable nodes.Moreover, this disclosure contemplates any suitable electrodes disposedon any suitable number of any suitable substrates in any suitablepatterns.

As described above, a change in capacitance at a capacitive node oftouch sensor 10 may indicate a touch or proximity input at the positionof the capacitive node. Touch-sensor controller 12 may detect andprocess the change in capacitance to determine the presence and locationof the touch or proximity input. Touch-sensor controller 12 may thencommunicate information about the touch or proximity input to one ormore other components (such one or more central processing units (CPUs))of a device that includes touch sensor 10 and touch-sensor controller12, which may respond to the touch or proximity input by initiating afunction of the device (or an application running on the device).Although this disclosure describes a particular touch-sensor controllerhaving particular functionality with respect to a particular device anda particular touch sensor, this disclosure contemplates any suitabletouch-sensor controller having any suitable functionality with respectto any suitable device and any suitable touch sensor.

Touch-sensor controller 12 may be one or more integrated circuits (ICs),such as for example general-purpose microprocessors, microcontrollers,programmable logic devices (PLDs) or programmable logic arrays (PLAs),application-specific ICs (ASICs). In particular embodiments,touch-sensor controller 12 comprises analog circuitry, digital logic,and digital non-volatile memory. In particular embodiments, touch-sensorcontroller 12 is disposed on a flexible printed circuit (FPC) bonded tothe substrate of touch sensor 10, as described below. The FPC may beactive or passive, where appropriate. In particular embodiments multipletouch-sensor controllers 12 are disposed on the FPC. Touch-sensorcontroller 12 may include a processor unit, a drive unit, a sense unit,and a storage unit. The drive unit may supply drive signals to the driveelectrodes of touch sensor 10. The sense unit may sense charge at thecapacitive nodes of touch sensor 10 and provide measurement signals tothe processor unit representing capacitances at the capacitive nodes.The processor unit may control the supply of drive signals to the driveelectrodes by the drive unit and process measurement signals from thesense unit to detect and process the presence and location of a touch orproximity input within the touch-sensitive area(s) of touch sensor 10.The processor unit may also track changes in the position of a touch orproximity input within the touch-sensitive area(s) of touch sensor 10.The storage unit may store programming for execution by the processorunit, including programming for controlling the drive unit to supplydrive signals to the drive electrodes, programming for processingmeasurement signals from the sense unit, and other suitable programming,where appropriate. Although this disclosure describes a particulartouch-sensor controller having a particular implementation withparticular components, this disclosure contemplates any suitabletouch-sensor controller having any suitable implementation with anysuitable components.

Tracks 14 of conductive material disposed on the substrate of touchsensor 10 may couple the drive or sense electrodes of touch sensor 10 toconnection pads 16, also disposed on the substrate of touch sensor 10.As described below, connection pads 16 facilitate coupling of tracks 14to touch-sensor controller 12. Tracks 14 may extend into or around (e.g.at the edges of) the touch-sensitive area(s) of touch sensor 10.Particular tracks 14 may provide drive connections for couplingtouch-sensor controller 12 to drive electrodes of touch sensor 10,through which the drive unit of touch-sensor controller 12 may supplydrive signals to the drive electrodes. Other tracks 14 may provide senseconnections for coupling touch-sensor controller 12 to sense electrodesof touch sensor 10, through which the sense unit of touch-sensorcontroller 12 may sense charge at the capacitive nodes of touch sensor10. Tracks 14 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, the conductivematerial of tracks 14 may be copper or copper-based and have a width ofapproximately 100 μm or less. As another example, the conductivematerial of tracks 14 may be silver or silver-based and have a width ofapproximately 100 μm or less. In particular embodiments, tracks 14 maybe made of ITO in whole or in part in addition or as an alternative tofine lines of metal or other conductive material. Although thisdisclosure describes particular tracks made of particular materials withparticular widths, this disclosure contemplates any suitable tracks madeof any suitable materials with any suitable widths. In addition totracks 14, touch sensor 10 may include one or more ground linesterminating at a ground connector (which may be a connection pad 16) atan edge of the substrate of touch sensor 10 (similar to tracks 14).

Connection pads 16 may be located along one or more edges of thesubstrate, outside the touch-sensitive area(s) of touch sensor 10. Asdescribed above, touch-sensor controller 12 may be on an FPC. Connectionpads 16 may be made of the same material as tracks 14 and may be bondedto the FPC using an anisotropic conductive film (ACF). Connection 18 mayinclude conductive lines on the FPC coupling touch-sensor controller 12to connection pads 16, in turn coupling touch-sensor controller 12 totracks 14 and to the drive or sense electrodes of touch sensor 10. Inanother embodiment, connection pads 16 may be connected to anelectro-mechanical connector (such as a zero insertion forcewire-to-board connector); in this embodiment, connection 18 may not needto include an FPC. This disclosure contemplates any suitable connection18 between touch-sensor controller 12 and touch sensor 10.

FIG. 2 illustrates an example exterior of an example active stylus 20.Active stylus 20 may include one or more components, such as buttons 30or sliders 32 and 34 integrated with an outer body 22. These externalcomponents may provide for interaction between active stylus 20 and auser or between a device and a user. As an example and not by way oflimitation, interactions may include communication between active stylus20 and a device, enabling or altering functionality of active stylus 20or a device, or providing feedback to or accepting input from one ormore users. The device may by any suitable device, such as, for exampleand without limitation, a desktop computer, laptop computer, tabletcomputer, personal digital assistant (PDA), smartphone, satellitenavigation device, portable media player, portable game console, kioskcomputer, point-of-sale device, or other suitable device. Although thisdisclosure provides specific examples of particular componentsconfigured to provide particular interactions, this disclosurecontemplates any suitable component configured to provide any suitableinteraction. Active stylus 20 may have any suitable dimensions withouter body 22 made of any suitable material or combination of materials,such as, for example and without limitation, plastic or metal. Inparticular embodiments, exterior components (e.g. 30 or 32) of activestylus 20 may interact with internal components or programming of activestylus 20 or may initiate one or more interactions with one or moredevices or other active styluses 20.

As described above, actuating one or more particular components mayinitiate an interaction between active stylus 20 and a user or betweenthe device and the user. Components of active stylus 20 may include oneor more buttons 30 or one or more sliders 32 and 34. As an example andnot by way of limitation, buttons 30 or sliders 32 and 34 may bemechanical or capacitive and may function as a roller, trackball, orwheel. As another example, one or more sliders 32 or 34 may function asa vertical slider 34 aligned along a longitudinal axis, while one ormore wheel sliders 32 may be aligned along the circumference of activestylus 20. In particular embodiments, capacitive sliders 32 and 34 orbuttons 30 may be implemented using one or more touch-sensitive areas.Touch-sensitive areas may have any suitable shape, dimensions, location,or be made from any suitable material. As an example and not by way oflimitation, sliders 32 and 34 or buttons 30 may be implemented usingareas of flexible mesh formed using lines of conductive material. Asanother example, sliders 32 and 34 or buttons 30 may be implementedusing a FPC.

Active stylus 20 may have one or more components configured to providefeedback to or accepting feedback from a user, such as, for example andwithout limitation, tactile, visual, or audio feedback. Active stylus 20may include one or more ridges or grooves 24 on its outer body 22.Ridges or grooves 24 may have any suitable dimensions, have any suitablespacing between ridges or grooves, or be located at any suitable area onouter body 22 of active stylus 20. As an example and not by way oflimitation, ridges 24 may enhance a user's grip on outer body 22 ofactive stylus 20 or provide tactile feedback to or accept tactile inputfrom a user. Active stylus 20 may include one or more audio components38 capable of transmitting and receiving audio signals. As an exampleand not by way of limitation, audio component 38 may contain amicrophone capable of recording or transmitting one or more users'voices. As another example, audio component 38 may provide an auditoryindication of a power status of active stylus 20. Active stylus 20 mayinclude one or more visual feedback components 36, such as alight-emitting diode (LED) indicator. As an example and not by way oflimitation, visual feedback component 36 may indicate a power status ofactive stylus 20 to the user.

One or more modified surface areas 40 may form one or more components onouter body 22 of active stylus 20. Properties of modified surface areas40 may be different than properties of the remaining surface of outerbody 22. As an example and not by way of limitation, modified surfacearea 40 may be modified to have a different texture, temperature, orelectromagnetic characteristic relative to the surface properties of theremainder of outer body 22. Modified surface area 40 may be capable ofdynamically altering its properties, for example by using hapticinterfaces or rendering techniques. A user may interact with modifiedsurface area 40 to provide any suitable functionally. For example andnot by way of limitation, dragging a finger across modified surface area40 may initiate an interaction, such as data transfer, between activestylus 20 and a device.

One or more components of active stylus 20 may be configured tocommunicate data between active stylus 20 and the device. For example,active stylus 20 may include one or more tips 26 or nibs. Tip 26 mayinclude one or more electrodes configured to communicate data betweenactive stylus 20 and one or more devices or other active styluses. Tip26 may be made of any suitable material, such as a conductive material,and have any suitable dimensions, such as, for example, a diameter of 1mm or less at its terminal end. Active stylus 20 may include one or moreports 28 located at any suitable location on outer body 22 of activestylus 20. Port 28 may be configured to transfer signals or informationbetween active stylus 20 and one or more devices or power sources. Port28 may transfer signals or information by any suitable technology, suchas, for example, by universal serial bus (USB) or Ethernet connections.Although this disclosure describes and illustrates a particularconfiguration of particular components with particular locations,dimensions, composition and functionality, this disclosure contemplatesany suitable configuration of suitable components with any suitablelocations, dimensions, composition, and functionality with respect toactive stylus 20.

FIG. 3 illustrates an example internal components of example activestylus 20. Active stylus 20 may include one or more internal components,such as a controller 50, sensors 42, memory 44, or power source 48. Inparticular embodiments, one or more internal components may beconfigured to provide for interaction between active stylus 20 and auser or between a device and a user. In other particular embodiments,one or more internal components, in conjunction with one or moreexternal components described above, may be configured to provideinteraction between active stylus 20 and a user or between a device anda user. As an example and not by way of limitation, interactions mayinclude communication between active stylus 20 and a device, enabling oraltering functionality of active stylus 20 or a device, or providingfeedback to or accepting input from one or more users.

Controller 50 may be a microcontroller or any other type of processorsuitable for controlling the operation of active stylus 20. Controller50 may be one or more ICs—such as, for example, general-purposemicroprocessors, microcontrollers, PLDs, PLAs, or ASICs. Controller 50may include a processor unit, a drive unit, a sense unit, and a storageunit. The drive unit may supply signals to electrodes of tip 26 throughcenter shaft 41. The drive unit may also supply signals to control ordrive sensors 42 or one or more external components of active stylus 20.The sense unit may sense signals received by electrodes of tip 26through center shaft 41 and provide measurement signals to the processorunit representing input from a device. The sense unit may also sensesignals generated by sensors 42 or one or more external components andprovide measurement signals to the processor unit representing inputfrom a user. The processor unit may control the supply of signals to theelectrodes of tip 26 and process measurement signals from the sense unitto detect and process input from the device. The processor unit may alsoprocess measurement signals from sensors 42 or one or more externalcomponents. The storage unit may store programming for execution by theprocessor unit, including programming for controlling the drive unit tosupply signals to the electrodes of tip 26, programming for processingmeasurement signals from the sense unit corresponding to input from thedevice, programming for processing measurement signals from sensors 42or external components to initiate a pre-determined function or gestureto be performed by active stylus 20 or the device, and other suitableprogramming, where appropriate. As an example and not by way oflimitation, programming executed by controller 50 may electronicallyfilter signals received from the sense unit. Although this disclosuredescribes a particular controller 50 having a particular implementationwith particular components, this disclosure contemplates any suitablecontroller having any suitable implementation with any suitablecomponents.

In particular embodiments, active stylus 20 may include one or moresensors 42, such as touch sensors, gyroscopes, accelerometers, contactsensors, or any other type of sensor that detect or measure data aboutthe environment in which active stylus 20 operates. Sensors 42 maydetect and measure one or more characteristic of active stylus 20, suchas acceleration or movement, orientation, contact, pressure on outerbody 22, force on tip 26, vibration, or any other suitablecharacteristic of active stylus 20. As an example and not by way oflimitation, sensors 42 may be implemented mechanically, electronically,or capacitively. As described above, data detected or measured bysensors 42 communicated to controller 50 may initiate a pre-determinedfunction or gesture to be performed by active stylus 20 or the device.In particular embodiments, data detected or received by sensors 42 maybe stored in memory 44. Memory 44 may be any form of memory suitable forstoring data in active stylus 20. In other particular embodiments,controller 50 may access data stored in memory 44. As an example and notby way of limitation, memory 44 may store programming for execution bythe processor unit of controller 50. As another example, data measuredby sensors 42 may be processed by controller 50 and stored in memory 44.

Power source 48 may be any type of stored-energy source, includingelectrical or chemical-energy sources, suitable for powering theoperation of active stylus 20. In particular embodiments, power source48 may be charged by energy from a user or device. As an example and notby way of limitation, power source 48 may be a rechargeable battery thatmay be charged by motion induced on active stylus 20. In otherparticular embodiments, power source 48 of active stylus 20 may providepower to or receive power from the device. As an example and not by wayof limitation, power may be inductively transferred between power source48 and a power source of the device.

FIG. 4 illustrates an example active stylus 20 with an example device52. Device 52 may have a display (not shown) and a touch sensor with atouch-sensitive area 54. Device 52 display may be a liquid crystaldisplay (LCD), a LED display, a LED-backlight LCD, or other suitabledisplay and may be visible though a cover panel and substrate (and thedrive and sense electrodes of the touch sensor disposed on it) of device52. Although this disclosure describes a particular device display andparticular display types, this disclosure contemplates any suitabledevice display and any suitable display types.

Device 52 electronics may provide the functionality of device 52. Asexample and not by way of limitation, device 52 electronics may includecircuitry or other electronics for wireless communication to or fromdevice 52, execute programming on device 52, generating graphical orother user interfaces (UIs) for device 52 display to display to a user,managing power to device 52 from a battery or other power source, takingstill pictures, recording video, other suitable functionality, or anysuitable combination of these. Although this disclosure describesparticular device electronics providing particular functionality of aparticular device, this disclosure contemplates any suitable deviceelectronics providing any suitable functionality of any suitable device.

In particular embodiments, active stylus 20 and device 52 may besynchronized prior to communication of data between active stylus 20 anddevice 52. As an example and not by way of limitation, active stylus 20may be synchronized to device through a pre-determined bit sequencetransmitted by the touch sensor of device 52. As another example, activestylus 20 may be synchronized to device by processing the drive signaltransmitted by drive electrodes of the touch sensor of device 52. Activestylus 20 may interact or communicate with device 52 when active stylus20 is brought in contact with or in proximity to touch-sensitive area 54of the touch sensor of device 52. In particular embodiments, interactionbetween active stylus 20 and device 52 may be capacitive or inductive.As an example and not by way of limitation, when active stylus 20 isbrought in contact with or in the proximity of touch-sensitive area 54of device 52, signals generated by active stylus 20 may influencecapacitive nodes of touch-sensitive area of device 52 or vice versa. Asanother example, a power source of active stylus 20 may be inductivelycharged through the touch sensor of device 52, or vice versa. Althoughthis disclosure describes particular interactions and communicationsbetween active stylus 20 and device 52, this disclosure contemplates anysuitable interactions and communications through any suitable means,such as mechanical forces, current, voltage, or electromagnetic fields.

In particular embodiments, measurement signal from the sensors of activestylus 20 may initiate, provide for, or terminate interactions betweenactive stylus 20 and one or more devices 52 or one or more users, asdescribed above. Interaction between active stylus 20 and device 52 mayoccur when active stylus 20 is contacting or in proximity to device 52.As an example and not by way of limitation, a user may perform a gestureor sequence of gestures, such as shaking or inverting active stylus 20,whilst active stylus 20 is hovering above touch-sensitive area 54 ofdevice 52. Active stylus may interact with device 52 based on thegesture performed with active stylus 20 to initiate a pre-determinedfunction, such as authenticating a user associated with active stylus 20or device 52. Although this disclosure describes particular movementsproviding particular types of interactions between active stylus 20 anddevice 52, this disclosure contemplates any suitable movementinfluencing any suitable interaction in any suitable way.

As described above in connection with FIG. 1, in particular embodiments,a touch sensor (e.g., touch sensor 10 illustrated in FIG. 1) may includean array of drive and sense electrodes or an array of electrodes of asingle type. These electrodes may be coupled to a controller (e.g.,controller 12 illustrated in FIG. 1) by specific tracks (e.g., tracks 14illustrated in FIG. 1). The drive unit of the controller may supplydrive signals to the drive electrodes through some tracks, and the senseunit of the controller may sense charge at the capacitive nodes throughother tracks. The electrodes may be arranged in various patterns andthis disclosure contemplates any suitable patterns for the electrodearrangements. For example, FIG. 5 illustrates an example array ofelectrodes arranged in a X-Y grid pattern. In particular embodiments,the drive electrodes may be arranged along one set of lines (e.g., the Xlines: X₁ to X_(n)) and the sense electrodes may be arranged alonganother set of lines (e.g., the Y lines: Y₁ to Y_(n)). The capacitivenodes are at one or more intersections of the X and Y lines. Atouch-sensitive area 500 may be populated with these electrodes.

In particular embodiments, to determine the location of an object, suchas a stylus or a user's finger, within a touch-sensitive area (e.g.,touch-sensitive area 500), a scan of the electrodes or coordinateswithin the touch-sensitive area may be performed (e.g., driving thedrive electrodes and scanning the capacitive nodes withintouch-sensitive area 500). In some implementations, the drive electrodesare driven one line at a time. More specifically, a number of pulses(e.g., 3 or 4 pulses) is sent down each line of drive electrodes (e.g.,each X line), and for each pulse, a number of signal samples (e.g., 1 or2 samples) is read by scanning the corresponding capacitive nodes. Forexample, in FIG. 5, the drive electrodes along the X₁ line may be drivenfirst; the charge is transferred through the capacitive coupling betweenthe drive and sense lines; and the corresponding capacitive nodes alongthe Y lines (e.g., Y₁ to Y_(n)) may be scanned to take the signalsamples. Then, the drive electrodes along the X₂ line are driven next;the charge is again transferred through the capacitive coupling betweenthe drive and sense lines; and the corresponding capacitive nodes alongthe Y lines are scanned to take the signal samples. And so on, until theelectrodes down the last line, X_(n), are driven and the correspondingcapacitive nodes down the Y lines are scanned to take the signalsamples. The samples may be digitally quantized (e.g., via ananalog-to-digital converter (ADC)). The digital samples are thentransmitted in individual frames. In particular embodiments, a frameincludes a full scan of some or all the capacitive nodes within atouch-sensitive area. As an example, in the case illustrated in FIG. 5,a frame includes [M×N] samples, where N denotes the number of X lines(e.g., drive lines) and M denotes the number of receive line.

In particular embodiments, active stylus 20 receives the signal orsignals from one or more drive lines (e.g., the X lines in its vicinity)of device 52. The stylus (e.g., active stylus 20) may then process thisreceived signal to create another signal to transmit back to device 52.As an example, the stylus may transmit a function of the received signal(whether linear or non-linear) that is then multiplied by a gain andthat may be added to an offset value. Thus, if R is the signal receivedat active stylus 20 (e.g., from device 52), T is the signal transmittedby active stylus 20 (e.g., back to device 52), f is a function (whetherlinear or non-linear), A is a gain factor, and B is an offset, thetransmitted signal T may be written as:T=A*f(R)+B.The signal R received by the stylus may be the series of pulses sentdown each drive line that active stylus 20 is able to detect. Inparticular embodiments, the signal T transmitted by the stylus may alsobe a series of pulses. The transmitted signal T will create a transferof charge through capacitive coupling between active stylus 20 and thesense lines (e.g., Y₁ to Y_(n)) of touch-sensitive area 500. Device 52,and, in particular embodiments, touch controller 12 may then receivesamples of transmitted signal T via a scan of the nodes along the senselines of touch-sensitive area 500. As described above, these samples maybe digitally quantized and may be transmitted in individual frames (eachframe including, for example, a full scan of the capacitive nodes intouch-sensitive area 500).

Active stylus 20 may transmit additional data to device 52 or touchcontroller 12 via the pulses that make up the transmitted signal T. Asan example, active stylus 20 may transmit data regarding stylus statusor information gathered from sensors 42 (e.g., pressure data, touchdata, accelerometer data, or gyroscope data), power source 48 (e.g.,battery life), electrodes in active stylus tip 26, memory 44, controller50, buttons 30 (e.g. whether a button has been pressed), sliders 32, orany other data gathered by any other component of active stylus 20.

The stylus may transmit this data to device 52 or touch controller 12 bymodulating the data onto the pulses that make up transmitted signal T.The modulation of the data may occur, for example, in controller 50 andbe transmitted via center shaft 41 and through electrodes in activestylus tip 26. As an example of data modulation, active stylus 20 maychange the amplitude (i.e., amplitude shift keying including on-offkeying), phase (i.e., phase shift keying), or frequency (i.e., frequencyshift keying) of the pulses sent in order to transmit information. Inparticular embodiments, this modulation of the data may include changingthe amplitude by changing the gain A used to create transmitted signalT. In yet other embodiments, this modulation of the data may includechanging the amplitude by changing the offset B used to createtransmitted signal T. In yet other embodiments, the modulation of thedata may include changing the frequency or phase by changing thefunction f used to create transmitted signal T.

In particular embodiments, active stylus 20 may transmit modulated dataon a pulse-by-pulse basis. As an example, the stylus may wish totransmit information regarding pressure data gathered from a pressuresensor. The stylus may digitize this pressure information using ananalog-to-digital converter (ADC). The bits of the digitized pressureinformation value may be transmitted by the stylus such that one bit ofdata is transmitted per pulse. If, in this example, the stylus usesamplitude shift keying to modulate the data, then at each pulse, thestylus will adjust the amplitude of the pulse to be one of two pre-setamplitude values. In the case of on-off shift keying, the amplitudevalue that represents the binary value “0” is itself 0, and the secondamplitude value may represent the binary value “1.” The touch controller12 may know the pre-set amplitude values, as well, and with thisinformation may demodulate the bit stream sent through the series ofpulses and recover the pressure data. Thus, in this manner, the bitsthat encode the value of the pressure information may be transmitted oneat a time, one bit per pulse transmitted, using variations in theamplitudes of the pulses.

FIG. 6 illustrates an example embodiment of the transmission of datafrom active stylus 20 to touch controller 12 on a pulse-by-pulse basisusing on-off keying. Pulses 611 and 612 each have an amplitude of ‘a’,which may represent the binary value “0.” Pulses 622 and 623 each havean amplitude of ‘b’, which may represent the binary value “1.” Thus, thebit stream of FIG. 6 conveys the bits “0” “0” “0” “1” “1” “1” “0” “0”“0” from active stylus 20 to touch controller 12. Amplitude values ‘a’and ‘b’ form the set of two amplitude values that both active stylus andtouch controller 12 know, so that the signal may be demodulated by touchcontroller 12.

Although the foregoing example described digital modulation of data on apulse-by-pulse basis, analog data may also be modulated on apulse-by-pulse basis. As an example, if the pressure data is notdigitized, it may still be conveyed from the stylus to device 52 orcontroller 12 using amplitude changes in the pulses. In this example,the value of the analog pressure data may be added to the standardoffset value B for each pulse. By doing this, the amplitude of eachpulse can convey the actual, analog value of the pressure data. Touchcontroller 12 may, in particular embodiments, recover the value of thepressure data by knowing the value B ahead of time (and subtracting Bfrom the amplitude of the pulse received from the stylus). Each pulse inthis example, therefore, conveys more than simply one bit of informationit conveys the actual value of the pressure data. In particularembodiments, the value of the pressure data may be quantized.

In particular embodiments, active stylus 20 may transmit modulated dataon a frame-by-frame basis. As an example, the stylus may wish totransmit information regarding pressure data gathered from a pressuresensor. The stylus may digitize this pressure information using ananalog-to-digital converter (ADC). The bits of the digitized pressureinformation value may be transmitted by the stylus such that one bit ofdata is transmitted per frame. Thus, if the frame rate is 200 Hz, thedata rate (given one bit per frame) would be 200 bits per second. If, inthis example, the stylus uses amplitude shift keying to modulate thedata, then at each frame, the stylus will choose one of two pre-setamplitude values to use for every pulse transmitted in that frame. Inthe case of on-off shift keying, the amplitude value that represents thebinary value “0” is itself 0, and the second amplitude value mayrepresent the binary value “1.” The touch controller 12 may know thepre-set amplitude values, as well, and with this information maydemodulate the bit stream sent through the series of frames (i.e., thechanging pulse amplitudes from frame to frame) and recover the pressuredata. Thus, in this manner, the bits that encode the value of thepressure information may be transmitted one at a time, one bit per frametransmitted, using variations in the amplitudes of the pulses.

Although the foregoing example described digital modulation of data on aframe-by-frame basis, analog data may also be modulated on aframe-by-frame basis. As an example, if the pressure data is notdigitized, it may still be conveyed from the stylus to device 52 ortouch controller 12 using amplitude changes in the pulses. In thisexample, the value of the analog pressure data may be added to thestandard offset value B for every pulse in a frame. By doing this, theamplitude of the pulses in a frame can convey the actual, analog valueof the pressure data. Touch controller 12 may, in particularembodiments, recover the value of the pressure data by knowing the valueB ahead of time (and subtracting B from the amplitude of the pulsesreceived in a frame from the stylus). Each frame in this example,therefore, conveys more than simply one bit of information—it conveysthe actual value of the pressure data. In particular embodiments, thevalue of the pressure data may be quantized.

In particular embodiments, each data-conveying unit (whether a frame ora pulse) may convey data in and of itself, or, alternatively, it mayconvey data in a differential form through comparison to prior (orfuture) data units. As an example, active stylus 20 may transmit analogpressure data on a frame-by-frame basis using amplitude modulation.Active stylus 20 may, in each frame, convey the analog pressure datavalue by adding this value to the amplitude of each pulse in the frame(e.g., adding the value to offset B, a value that touch controller 12knows), thereby conveying the pressure data directly. Alternatively,active stylus 20 may differentially convey the pressure data by addingthe pressure data value to the value of the amplitude of the pulses inthe previous frame and using this new amplitude value for all the pulsesin the current frame. Touch controller 12 may recover the pressure datavalue (without needing any reference information like B) by simplysubtracting the amplitude of a pulse of the current frame from theamplitude of a pulse of the previous frame. The choice of frame-based orpulse-based data transmission may, in particular embodiments, depend onthe type of data being transmitted. As examples, pressure data may betransmitted on a pulse-by-pulse basis, and battery life information orinput from buttons may be transmitted on a frame-by-frame basis.

Although the specific examples discussed above illustrate the use ofon-off keying or amplitude shift keying, active stylus 20 may also usefrequency shift keying, phase shift keying, or any other suitable datamodulation scheme to transmit data (whether digital or analog) on apulse-by-pulse or frame-by-frame basis. In particular embodiments, bothframe-based and pulse-based communication schemes may be usedsimultaneously by active stylus 20 and device 52. Active stylus 20 mayencode the data (using, e.g., error-correcting codes) or add a packetheader describing the data packet's contents or encoding beforetransmitting it to device 52 or touch controller 12. Data may betransmitted in groups other than pulses or frames encompassing theentire touch-sensor area. For example, data may be transmitted on afraction of a frame basis. Data transmission may, in particularembodiments, occur on the same communication layer (e.g., physicallayer) regardless of whether the data is transmitted per frame or perfraction of a frame. Different types of data (e.g. pressure and batterylife) may be communicated in a time-multiplexed manner between pulses orframes. Touch controller 12 may have the same logic as active stylus 20for the transmission or receipt of data using any of the communicationschemes described.

FIG. 7A illustrates an example method for communicating modulated databetween active stylus 20 and device 52, including touch controller 12.The method may start at step 710, where active stylus 20 receives sensordata from sensors 42. At step 720, active stylus 20 waits to receive acarrier signal from touch controller 12. At step 730, a carrier signalis generated by touch controller 12 and transmitted to active stylus 20.At step 740, the carrier signal is modulated by active stylus 20 toinclude the sensor data so that the sensor data may be communicated fromactive stylus 20 to touch controller 12. At step 750, the modulatedcarrier signal including the sensor data is transmitted from activestylus 20 to touch controller 12. In particular embodiments, steps 710,720, 740, and 750 may occur in controller 50 of active stylus 20. Atstep 760, touch controller 12 receives the modulated carrier signalincluding the sensor data. At step 770, touch controller 12 demodulatesthe carrier signal and extracts the sensor data. In particularembodiments, the steps illustrated in FIG. 7A may be repeated any numberof times (e.g., any number of iterations). For example, during a seconditeration, a second carrier signal may be modulated with sensor data(whether the same sensor data or different sensor data). This secondsignal may then be transmitted at step 750. Although this disclosuredescribes and illustrates particular steps of the method of FIG. 7A asoccurring in a particular order, this disclosure contemplates anysuitable steps of the method of FIG. 7A occurring in any suitable order.Furthermore, although this disclosure describes and illustratesparticular components, devices, or systems carrying out particular stepsof the method of FIG. 7A, this disclosure contemplates any suitablecombination of any suitable components, devices, or systems carrying outany suitable steps of the method of FIG. 7A.

FIG. 7B illustrates another example method for communicating modulateddata between active stylus 20 and device 52, including touch controller12. The method may start at step 715, where active stylus 20 receivessensor data from sensors 42. At step 725, active stylus 20 generates acarrier signal. At step 735, the carrier signal is modulated by activestylus 20 to include the sensor data so that the sensor data may becommunicated from active stylus 20 to touch controller 12. At step 745,the modulated carrier signal including the sensor data is transmittedfrom active stylus 20 to touch controller 12. In particular embodiments,steps 715-745 may occur in controller 50 of active stylus 20. At step755, touch controller 12 receives the modulated carrier signal includingthe sensor data. At step 765, touch controller 12 demodulates thecarrier signal and extracts the sensor data. In particular embodiments,the steps illustrated in FIG. 7B may be repeated any number of times(e.g., any number of iterations). For example, during a seconditeration, a second carrier signal may be modulated with sensor data(whether the same sensor data or different sensor data). This secondsignal may then be transmitted at step 745. Although this disclosuredescribes and illustrates particular steps of the method of FIG. 7B asoccurring in a particular order, this disclosure contemplates anysuitable steps of the method of FIG. 7B occurring in any suitable order.Furthermore, although this disclosure describes and illustratesparticular components, devices, or systems carrying out particular stepsof the method of FIG. 7B, this disclosure contemplates any suitablecombination of any suitable components, devices, or systems carrying outany suitable steps of the method of FIG. 7B.

In particular embodiments, modulated data may also be communicated fromdevice 52, including touch controller 12, to active stylus 20. As anexample, touch controller 12 may gather data (e.g., control data orcommand data) from device 52 (including, for example, touch-sensitivearea 500), modulate a carrier signal to include the data, and transmitthe data to active stylus 20. In particular embodiments, the carriersignal may be generated by active stylus 20 and transmitted to touchcontroller 12 for modulation by touch controller 12. In otherembodiments, the carrier signal may be generated by touch controller 12and modulated by touch controller 12. In yet other embodiments, bothactive stylus 20 and touch controller 12 may generate the carrier signalfor modulation. Additionally, active stylus 20 may receive the modulatedcarrier signal, demodulate the carrier signal, and extract the data inthe signal. The carrier signal may, in particular embodiments, bemodulated by active stylus 20, touch controller 12, or both. In yetother embodiments, two or more carrier signals may be generated ormodulated by both active stylus 20 and touch controller 12, eithersimultaneously or at different times, providing for implementations offrequency or phase modulation. Any or all of the variations or exampleembodiments discussed with respect to the transmission of modulated datafrom active stylus 20 to touch controller 12 (including, for example,the type of modulation scheme) may be applied to the transmission ofmodulated data from touch controller 12 to active stylus 20, and viceversa.

In particular embodiments, active stylus 20 works in synchronizationwith touch controller 12. In these embodiments, active stylus 20 maydetect a drive signal from the drive lines of touch-sensitive area 500and reply back to touch controller 12 within a touch-sensing time windowof the touch controller 12. Touch controller 12 may scan thetouch-sensitive area 500 until it detects active stylus 20, and once ithas detected active stylus 20, it may use a “handshake” to confirmbefore transmitting data to active stylus 20. Touch controller 12 maydetect the stylus or synchronize with the stylus based on the nature ofthe stylus response signal (including, for example, side lobes of thestylus response due to non-linear gain at the stylus). Once activestylus 20 is detected, touch controller 12 may transmit a variablenumber of extra pulses down one or more drive lines (e.g., the X linesillustrated in FIG. 5) of touch-sensitive area 500. Active stylus 20may, upon seeing these extra pulses, respond in a pre-determined fashion(e.g., a signature or code). After this handshake, touch controller 12may cease to drive any X lines and may continue to listen fortransmissions from active stylus 20. Active stylus 20 may then transmitdata using any of the data communication schemes described. The stylusmay maintain a counter with data about past pulses it has received fromdevice 52 (including touch-sensitive area 500 or touch controller 12) orpulses it has transmitted. Once active stylus 20 has completed its datatransmission, it may send a stop bit to let touch controller 12 knowthat it may restart its normal scanning or driving of touch-sensitivearea 500.

Herein, reference to a computer-readable non-transitory storage mediumencompasses a semiconductor-based or other integrated circuit (IC)(such, as for example, a field-programmable gate array (FPGA) or anapplication-specific IC (ASIC)), a hard disk, an HDD, a hybrid harddrive (HHD), an optical disc, an optical disc drive (ODD), amagneto-optical disc, a magneto-optical drive, a floppy disk, a floppydisk drive (FDD), magnetic tape, a holographic storage medium, asolid-state drive (SSD), a RAM-drive, a SECURE DIGITAL card, a SECUREDIGITAL drive, or another suitable computer-readable non-transitorystorage medium or a combination of two or more of these, whereappropriate. A computer-readable non-transitory storage medium may bevolatile, non-volatile, or a combination of volatile and non-volatile,where appropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Moreover,reference in the appended claims to an apparatus or system or acomponent of an apparatus or system being adapted to, arranged to,capable of, configured to, enabled to, operable to, or operative toperform a particular function encompasses that apparatus, system,component, whether or not it or that particular function is activated,turned on, or unlocked, as long as that apparatus, system, or componentis so adapted, arranged, capable, configured, enabled, operable, oroperative.

What is claimed is:
 1. A stylus comprising: one or more sensors; one ormore electrodes configured to communicate with a device by receivingsignals from and transmitting signals to a touch sensor of the device;and one or more computer-readable non-transitory storage media embodyinglogic that is operable when executed to: receive sensor data from theone or more sensors; receive a first signal generated by the device;generate a second signal by modulating a carrier signal based on thesensor data; and transmit to the device, in response to the firstsignal, the second signal, the sensor data being obtainable bydemodulating the second signal.
 2. The stylus of claim 1, wherein thefirst signal is the carrier signal modulated to generate the secondsignal.
 3. The stylus of claim 1, wherein the second signal is generatedusing one of: amplitude modulation; frequency modulation; and phasemodulation.
 4. The stylus of claim 1, wherein: the one or more sensorscomprise a pressure sensor and a button; and the sensor data comprisespressure data and button state data.
 5. The stylus of claim 1, whereinthe sensor data is digital.
 6. The stylus of claim 1, wherein the secondsignal is transmitted in a single electric pulse.
 7. One or morecomputer-readable non-transitory storage media embodying logic that isoperable when executed to: receive sensor data from one or more sensorsin or on a stylus, the stylus comprising one or more electrodesconfigured to communicate with a device by receiving signal from andtransmitting signals to a touch sensor of the device; receive a firstsignal generated by the device; generate a second signal by modulating acarrier signal based on the sensor data; and transmit to the device, inresponse to the first signal, the second signal, the sensor data beingobtainable by demodulating the second signal.
 8. The media of claim 7,wherein the first signal is the carrier signal modulated to generate thesecond signal.
 9. The media of claim 7, wherein the second signal isgenerated using one of: amplitude modulation; frequency modulation; andphase modulation.
 10. The media of claim 7, wherein: the one or moresensors comprise a pressure sensor and a button; and the sensor datacomprises pressure data and button state data.
 11. The media of claim 7,wherein the sensor data is digital.
 12. The media of claim 7, whereinthe second signal is transmitted in a single electric pulse.
 13. Asystem comprising: a device comprising a touch sensor; and a styluscomprising: one or more sensors; one or more electrodes configured tocommunicate with a device by receiving signals from and transmittingsignals to a touch sensor of the device; and one or morecomputer-readable non-transitory storage media embodying logic that isoperable when executed to: receive sensor data from the one or moresensors; receive a first signal generated by the device; generate asecond signal by modulating a carrier signal based on the sensor data;and transmit to the device, in response to the first signal, the secondsignal, the device being operable to obtain the sensor data bydemodulating the second signal.
 14. The system of claim 13, wherein thefirst signal is the carrier signal modulated to generate the secondsignal.
 15. The system of claim 13, wherein the second signal isgenerated using one of: amplitude modulation; frequency modulation; andphase modulation.
 16. The system of claim 13, wherein: the one or moresensors comprise a pressure sensor and a button; and the sensor datacomprises pressure data and button state data.
 17. The system of claim13, wherein the sensor data is digital.
 18. The system of claim 13,wherein the second signal is transmitted in a single electric pulse.